Research On Bi-directional DC/DC Converter For Battery Energy Storage System

With the rapid development of society,the development of the electric power system is facing many problems,such as load increasing,new energy access accounted for expansion,peak shaving means limited,which can cause a great danger to our life.Battery energy storage system which multiple requirements are relatively high,has been budgeted for power system construction.The main function of the battery energy storage system in power system is peak load shifting which can alleviate the contradiction of power supply load instability,increased the stability of power grid operation and improve the quality of power supply,and can promote the development and utilization of renewable energy.The bi-directional DC/DC converter acts as the core unit in the whole energy storage system,and its effect determines the quality of the whole battery energy storage system.Therefore,it is of great practical significance to study.This article based on the two level structure of energy conversion system of bi-directional DC/DC converter as the key research object.Through the domestic and foreign literature review and analyzing,this article determines the energy storage system design objectives,uses bidirectional half bridge topology with non-isolation type,and detailed introduces working principle for BUCK and BOOST and uses state space average method to derive the small signal model which provides basis for subsequent the design of the controller.This paper focused on the control strategy of battery charge and discharge,completed the design of constant current charging and discharging mode of battery by using the current loop,achieved a constant pressure on the battery charging by using outer loop voltage loop and inner current loop design of double closed loop,designed parameters of PI controller,and finally built a simulation model to verify the feasibility the parameters of the controller by using MTALAB simulation software.This paper designed the actual circuit required for bidirectional DC/DC converter in the system,including the selection of main circuit switch tube,energy storage inductor and capacitor design parameters,and gave the driver circuit and protection circuit design.By using the TMS320F28335 digital signal processor(DSP)and some interrupt subroutines.